If you’ve ever wondered what the “value” is of a consumer spending time online, we have some answers courtesy of SumAll, a data visualization company.

SumAll has tapped into Google Analytics data to study patterns across ~10,000 customers and nearly $1 billion worth of transactions. What it finds is that a minute of time spent by a consumer “e-window shopping” is worth an average of 43 cents.

SumAll also calculates that one full visit to an e-commerce site is worth ~$1.30.

The company has been tracking this sort of information for a number of years, so we have some comparative statistics we can observe. In 2012, SumAll finds that the average amount of time spent per site declined by approximately 14% — from 3 minutes, 16 seconds in 2011 to 2 minutes, 49 seconds today.

Despite that decrease in time spent per online visit, the revenue generated per visit actually grew by ~24%.

What’s the reason? “Buyers are more accustomed to buying online, so the hesitation is dropping,” Dane Atkinson, SumAll’s CEO claims.

The SumAll data also suggest that an average consumer spending 1 minute, 54 seconds on a site is the amount of time needed in order for the e-retailer to make a dollar in sales.

The SumAll report concludes that a balance needs to be struck on e-commerce sites between having enough depth to be interesting … but not so much as to be overwhelming, with too many products offered and/or undue difficulty in illuminating the payment path for buyers.

According to Atkinson, aiming for an average e-commerce visit of three to four minutes is a good goal for engaging customers without confusing them with too many options.

Finally, we see from the trend data that there has been a dramatic decrease in the amount of minutes spent on a site to result in a dollar sale: it was charted at over 5 minutes back in 2009, more than three times 2012’s findings.